Elastic deformation and gaseous rarefaction effects are of great importance to the static and dynamic characteristics of gas microbearings.Based on the effective viscosity model of Veijola,the flexibility matrix was established by finite element method to calculate the elastic deformation of bearing shell surface,and the modified Reynolds equation considering the influence of effective viscosity and elastic deformation was deduced.The effects of bearing elastic modulus,gas effective viscosity,bearing structural parameters and disturbance frequency on the static and dynamic characteristics were analyzed by solving the modified Reynolds equation,effective viscosity equation and elasticity equations of ultra-thin gas film lubrication.The results indicate that the gaseous rarefaction effect significantly reduces the load carrying capacity of microbearings.The load carrying capacity of microbearing increases with the increase of eccentricity ratio and bearing number.Increasing the flexibility of bearing shell can improve the load carrying capacity and friction coefficient of microbearings,while the bearing capacity and friction coefficient of elastic microbearings considering the effective viscosity of gas are small.Compared with the rigid bearing,the reduction of the elastic modulus of the bearing shell significantly increases the dynamic stiffness coefficient and reduces the direct damping coefficient of the microbearings,while considering the gas effective viscosity effect caused by the rarefaction effect reduces the direct stiffness and increases the direct damping coefficient of the microbearings